#ifndef _server_backend_h
#define _server_backend_h

#define LOCKFILE	"/tmp/calc_server.lockfile"

/* set signals handler */
void setSignalCatcher(void);

/* create and lock file */
void lockfile(void);

/* remove lock file */
void unlockfile(void);

/* makes an add operation */
double add(double op1, double op2); 

/* makes a substract operation */
double sub(double op1, double op2); 

/* makes a multiplication operation */
double mult(double op1, double op2); 

/* makes a division operation */
double divide(double op1, double op2); 

#endif
